Spybot S&D

I ran the latest update for SS&D - and under Detection Rules I get this msg: "Bad Cheksum!!" after I d/loaded/installed the update. What does this mean? Also, i usually d/l only Detection Rules...I don't update Main Skin, tea timer. etc. bcuz i don't enable TT. Am I supposed to d/l all these others besides detection rules? Thanks for this great forum and all the helpful moderators.